Protocols › Prebiotics

Prebiotics for bloating and gas

Goal: What trials used against bloating and gas. The evidence is small and mixed, and some prebiotics make gas worse.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 4 Nov 2026
Dose

2.75 g a day of a GOS mixture in 83 adults with gut symptoms.[1] 3.5 g a day in 44 people with irritable bowel syndrome. In that trial, less bloating and flatulence were reported at 3.5 g and not at 7 g.[2]

Form

A GOS mixture. In a 2019 review, types other than inulin-type fructans improved flatulence, and inulin-type fructans made it worse.[3]

How long

2 weeks on each treatment in the 83-person trial, with lower scores by the end of the first week.[1] The other trial lasted 12 weeks.[2]

What studies found

The 2 trials above found less bloating and flatulence.[1][2] A 2019 review of 11 trials with 729 adults found no overall benefit for bloating or flatulence. Flatulence improved at 6 g a day or less. No trial was at low risk of bias in every category.[3]

Ask a doctor first

Prebiotics can make gas and bloating worse, and side effects rise with dose.[4] In people with inflammatory bowel disease in remission who had gut symptoms, 12 g a day of fructans made symptoms worse.[5] GOS allergy has been described in people with allergies in Singapore.[6]

People with irritable bowel syndrome, inflammatory bowel disease or allergies should ask a doctor or pharmacist first.[5][7][6]

References

  1. Effect of a prebiotic galactooligosaccharide mixture (B-GOS®) on gastrointestinal symptoms in adults selected from a general population who suffer with bloating, abdominal pain, or flatulence. Vulevic J, Tzortzis G, Juric A, Gibson GR Neurogastroenterol Motil, 2018. PMID 30109908
  2. Clinical trial: the effects of a trans-galactooligosaccharide prebiotic on faecal microbiota and symptoms in irritable bowel syndrome. Silk DB, Davis A, Vulevic J, Tzortzis G, Gibson GR Aliment Pharmacol Ther, 2009. PMID 19053980
  3. Prebiotics in irritable bowel syndrome and other functional bowel disorders in adults: a systematic review and meta-analysis of randomized controlled trials. Wilson B, Rossi M, Dimidi E, Whelan K Am J Clin Nutr, 2019. PMID 30949662
  4. Prebiotics and Probiotics for Gastrointestinal Disorders. Rau S, Gregg A, Yaceczko S, Limketkai B Nutrients, 2024. PMID 38542689
  5. Fermentable Carbohydrates [FODMAPs] Exacerbate Functional Gastrointestinal Symptoms in Patients With Inflammatory Bowel Disease: A Randomised, Double-blind, Placebo-controlled, Cross-over, Re-challenge Trial. Cox SR, Prince AC, Myers CE, Irving PM, Lindsay JO, Lomer MC, et al. J Crohns Colitis, 2017. PMID 28525543
  6. Anaphylaxis to galacto-oligosaccharides--an evaluation in an atopic population in Singapore. Soh JY, Huang CH, Chiang WC, Llanora GV, Lee AJ, Loh W, et al. Allergy, 2015. PMID 25951913
  7. Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals With Irritable Bowel Syndrome. Major G, Pritchard S, Murray K, Alappadan JP, Hoad CL, Marciani L, et al. Gastroenterology, 2017. PMID 27746233